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Topic: LIDAR - in a way I can relate to (Read 3598 times)

This thread seems like it would be extremely interesting....as soon as someone translates it into "tech moron" for me.

Stuff that used to be tremendously expensive and require a team of engineers working for a year to put together can now be done by one guy in a weekend for the price of a pizza.

If you have a great idea for a device that does something worth while (or not) that involves things that you can determine using your senses, there are off shelf parts (electronic sensors) that hobbyists can cobble together pretty easily for not much money. Communicating between devices or your phone or the net is also not that hard or expensive. It can get a little more expensive if you want it to move around and do stuff, but that is still something that hobbyists can do.

So PonoBill talked me into ordering an ESP32. I have no idea what I am going to do with it.

I guess I will have to come up with something. I poked through my stuff and found a 3 wheel AV I abandoned when the builder for the runway inspector decided not to go forward. It has a couple of stepper motors for the back wheels. I was pushing that idea since we wanted more precise turning than you get with drive wheels in the back and steering in the front. The motors are weak though. It has a crappy little Arduino mini running it that has some issues; that's a candidate for the ESP32. I still have one of the high power xBees, which is pretty useless by itself, connected to yet another Arduino, GPS and tilt compensated compass. A rotary encoder. A fairly powerful brushless motor and ESC. Somewhere around here there's another Arduino that has the USB device settings and does some MIDI controller stuff. I think I have another box of sensors (like the Sharp IR) and I misplaced a little RC boat. This is what happens when I dabble with something and then stop messing with it for a while.

EDIT - found a bunch of sensors, but not the IR. I can't remember what half the stuff is; going to have to Google chip numbers.

I feel your pain. This is my little electronics corner in my garage in Maui. The one in Hood River is at least an order of magnitude more confusing. I'm constantly picking up a board and trying to figure out WTF it is.

Jeez... "as a preamble as it is a series of perfectly timed spikes high and low that is not likely to be random static." We had a 2-cyl JD tractor on my aunt's farm that was started with a flywheel. I am extremely fortunate that with decent hands and dumb luck, I have been able to run a little business for ~40yrs. I'd be still on the Concrete Gang if I was dependant on my brain. A friend who decided what went on DOD satellites has learned to throttle back the brainiac.

Here's my first attempt at 'marsh management'. FWD, articulated, hydro-driven. ...too heavy, too tall, too narrow. It 'worked' but I ended up getting chucked off when it fell in a hole ..then had to muscle it upright and back it out with the aid of planks/plywood ...me, a total mess schlepping around on snowshoes. I looked at making a sled with a reversible rope tow - parking a pontoon boat on the creek and anchoring the shore-end to trees, etc. The sled works - I tried it with an old truck hood, but too futsy. I also thought of a mega weed wacker that looked like a Gravely walk-behind but it looked too easily fouled and marsh-walking is not fun when you are also getting jerked around. (Phragmites are hollow and crush easily making a virtual roadbed.)

I bought two of the widest/longest snowmachine tracks, 'come up with a simple boogie system that my friend Hank will fab into a crawler. Its low profile and better traction should eliminate most of the issues I had with this monster. One imagines an opportunity to 'take the show on the road' and buried expenses in the future. There's a lot of property around the Chesapeake Bay with the same -recurring- issue.

I also thought of a mega weed wacker that looked like a Gravely walk-behind but it looked too easily fouled and marsh-walking is not fun when you are also getting jerked around. (Phragmites are hollow and crush easily making a virtual roadbed.)

Did you ever consider a front mounted sickle bar mower to mow 'em down instead of just smushing them?

I think you have headed the right way with your wide wheel rollers, they just weren't wide enough and floaty enough. I'd rework that contraption but make the rollers twice as wide and fill them with foam. If it was me, I'd make the thing autonomous, easy to do with GPS and nothing much to hit, or no big problem if it bumps something unyielding. But driving it works.

I think you have headed the right way with your wide wheel rollers, they just weren't wide enough and floaty enough. I'd rework that contraption but make the rollers twice as wide and fill them with foam. If it was me, I'd make the thing autonomous, easy to do with GPS and nothing much to hit, or no big problem if it bumps something unyielding. But driving it works.

When I did my first AV, I was poking around the net looking for code/info and found a project somebody did where they logged GPS while carrying the bot around, then set it own, flipped a switch and it drove itself back along the same route. You could do the same sort of thing with a removable head unit or a separate SD logger to walk the planned path first.

To get it perfect, I would want true zero turn radius, so at the pivots you turn 90, go forward the distance of the cut width, turn 90 again and start forward. GPS will be near worthless while pivoting.

There are some serious safety concerns letting something that leads with a power cutter run around autonomously. Not that a car going 45 would do any less damage but it has an array of sensors and safety countermeasures.

I looked at the LIDAR components. The "real" ones aren't cheap. There are TOF laser distance sensors that do use the same technology, but they aren't really LIDAR. I found some of those around $10 if I must have it now and $5 if slow boat from China is okay. I went the $5 route as I have a decent IR that functions identically from the software side to play with. I think I might use my little stepper motors to sweep side to side and up and down and see if I can generate a 3D representation of things that don't move much (or ever ) because it will not be fast, though at low granularity (like points 2" apart at 3' or whatever) it would be a little quicker.

I wouldn't do a sickle bar, just run them over. I was fiddling around and wrote the pseudocode for the idea that Ride described with some tweaks. I'm going to build a little fake version here after I finish the project I'm doing for my PT. The stuff for the motorhome can wait a bit. I modified the notion a little. You take your iPhone and use the compass/GPS. Go to each of the four corners of a rectangle to get squashed and get the coordinates. Enter them in the software (you could grab it right from the GPS app, but that looks like work), turn on the squasher and walk away. The Squasher code divides up the rectangle into GPS-directed paths a little narrower than the squasher width and then drives the paths, correcting after each 180.

I did something similar with navigation code for drones a few years ago. Flying a drone along an imaginary cable, like one of those cablecams. Pretty easy to do in the air with a drone though we crashed them into a lot of stuff. Headmount was with me when I was showing it off here in Maui. It hit some palm fronds hanging down flying the cable path and fell out of the sky. Unfortunately, there was a homeless guy riding a bicycle and it swooped down a bit out of control and buzzed up his leg with one of the props. Good thing he had on long pants. Din't really hurt him, just scared the shit out of both him and me.

I have an old robot lawnmower in Hood river that did random paths within a boundary signal wire. I never liked the random thing, and I couldn't come up with a way to make it mow the multiple levels of lawn we have in HR so it's just sitting. I bought the thing to do a huge lawn we had at our house in Portland. Didn't work well. But GPS guided--yeah. I could do a map, including travel paths where it didn't run the cutter. Both the squasher and my lawnmower could use a simple bumper or an IR object detector for avoidance. Implementation always is tougher than it seems, but this seems to be a worthy project that I could use as a base for a number of things.

If I get it going well I'll give you a version of it Wetstuff, to scare your neighbors with an autonomous squasher.

Are you going to do steppers in the back and swivels up front? If you do, electric wheelchair or mobility scooter parts are a good source. A common reason people use the scooters these days is obesity, so you can get some really high powered ones. The motors are ready to bolt on to a chassis, have the torque and are ready to wire. If you are lucky, you might find a wrecked scooter cheap.

I got motivated enough to set up a MEGA and breadboard to do some sensor and stepper motor work. Hopefully most code will port over to ESP32. Certainly any math work with coordinates will. Besides, it will only be a few days until I get the ESP32. I still am working on how/why I might use the web to get instructions and/or upload results.

I updated to latest Arduino dev environment and added ESP32 support. I was surprised at the length of the board list. It looks like there is less hardware standardization than on Arduino boars.

Thanks, Bill...'Ya, press on!' Unlike you guys, I am limited to a reservoir of manual/visual experience. My brain simply will not process 'electronics'. I am having a helluva fun/difficult time just dealing with security cams.

Sano, a sickle bar (I first did it by hand with a small scythe, then weed wacker) is really not needed; being hollow, when mature, they simply fold flat and mat. I attempted to use very large back tarps (heat+darkness) to stop re-growth, but they simply elevated the tarps. They look like asparagus when they first come up. I had a Gravley walk-behind and that sucker weighed as much as a small car. You are -up to your knees- in that soft muck where these thrive. I use snowshoes, waders are a bitch to suck back out of the muck.

Hmm...Alexa - that got my attention. Not sure exactly what I would do with it, but it starts more gears turning.

The irTOF distance sensor I had lying around, a Pololu VL6180X breakout (because I can't find that damn Sharp), I have dealt with before so I had code lying around. I have been reminded why I got the Sharp. The range is max 20 to 60 cm depending on scale factor. It reads out 0-200 and you multiply by the scale factor of 1, 2 or 3 to get mm. You set scale and it reduces resolution but increases range. That sounds okay except it bounces around so you have to get a few readings and vote. The high spikes are bigger than the low ones so I can't average them. It also returns ambient light readings. I spit out distance and ambiance readings every 750 ms in a loop and pointed it around and it became very obvious that above a given brightness, distance sensing goes to hell. Still worth playing with for now.

Sano, a sickle bar (I first did it by hand with a small scythe, then weed wacker) is really not needed; being hollow, when mature, they simply fold flat and mat. I attempted to use very large back tarps (heat+darkness) to stop re-growth, but they simply elevated the tarps. They look like asparagus when they first come up. I had a Gravley walk-behind and that sucker weighed as much as a small car. You are -up to your knees- in that soft muck where these thrive. I use snowshoes, waders are a bitch to suck back out of the muck.

Yeah, that's what happens when a SoCal kid weighs in on sheet he knows nothing about. As soon as I read "I use snowshoes" in the swamp...I know I was definitely out of my imaginary element.

Best of luck with whatever you (and the mad scientists...I say that with love, respect, and admiration) dream up. I'll for now. Lol.

That sounds okay except it bounces around so you have to get a few readings and vote. The high spikes are bigger than the low ones so I can't average them. It also returns ambient light readings. I spit out distance and ambiance readings every 750 ms in a loop and pointed it around and it became very obvious that above a given brightness, distance sensing goes to hell. Still worth playing with for now.

I confess I don't really know the difference between the expensive Lidar sensors (about $150) and the much cheaper Time of Flight sensors (about five bucks) which seems likely to be what is used in inexpensive measuring systems like the Stanley pocket laser measurer for 12 bucks.